Holt Heath Mire Restoration Project

Discover Holt Heath, an important lowland heath near Kingston Lacy, Dorset

The National Trust manages Holt Heath National Nature Reserve (NNR), for ever, for everyone. The Heath is one of the largest remaining areas of heathland in Dorset, and a Site of Special Scientific Interest (SSSI), which is visited and enjoyed by many throughout the year.

The mire system and surrounding wet heathland at Holt Heath is currently in unfavourable condition. This is because of an extensive network of historic ditches that criss-cross the area, some of which date from the medieval period.  These ditches are the result of peat cutting practices on the heathland in the past.  This network of ditches causes lots of water to run-off the heath resulting in the mire becoming much drier than desired, especially during the summer months.

Holt Heath National Nature Reserve (red line) with mire system criss-crossed with a network of historical ditches (blue lines) causing excessive water run-off from the heath.
Holt Heath National Nature Reserve (red line) with mire system criss-crossed with a network of historical ditches (blue lines) causing excessive water run-off from the heath.

Mires are wet and boggy areas that typically form peat by the laying down of sphagnum mosses. They are important habitats for interesting plants, animals and birds, such as the bogbean, cotton grass, marsh gentian, bog bush cricket and curlews which all rely on wet and boggy mires to flourish.

The delicate marsh gentian can be found in the mire habitat at Holt Heath
The delicate marsh gentian can be found in the mire habitat at Holt Heath

In late summer/early autumn of 2017, with the support of Natural England, we will be restoring the mire at Holt Heath, in order to return it back to a ‘favourable’ condition and to support the nature that relies on this area to survive and thrive.

In order to restore the mire we will be installing a series of plugs within the ditch network. This will slow the passage of water running off the heath and encourage it to flow sideways into the mire where it will form desirable shallow pools. The plugs will be a mixture of wooden shuttering and ‘peat blocks’ from the surrounding mire.  In total there will be 56 plugs installed at 50m intervals along approximately 3.50km of ditches. This will contribute to the restoration of around 98 hectares (242 acres) of the mire that is currently degraded.

Desirable shallow pools in the mire system provide a good habitat for the wildlife associated including the delicate marsh gentian
Desirable shallow pools in the mire system provide a good habitat for the wildlife associated including the delicate marsh gentian

We will also be doing work to upgrade part of the surface of the bridleway that comes off the Castleman Trailway at Newman’s Lane, giving better access throughout the year.

We plan to carry out the work between late August and early October, minimising disturbance to ground nesting birds whilst allowing the best access to the mire without causing excessive damage to the site.  During this time there will be minimal disruption to accessing the heath, or to vehicular access along Newman’s Lane.

Throughout the duration of the project information boards will be located at the entrance to the heath at Newman’s Lane, West Moors and at the entrance to Whitesheet car park, Holt.

If you would like more information about this project or have any queries please contact the Kingston Lacy office on: kingstonlacy@nationaltrust.org.uk  or call 01202 639460.